Cracking and buoyancy effect on hydrocarbon endothermic and heat transfer characteristics in rectangular mini-channel

doi:10.1016/j.cjche.2022.07.024

Abstract

Abstract: Although buoyancy and cracking reactions are strongly coupled in the active cooling process, most of the previous studies consider only one of these factors, and their coupling relationship has not been considerably examined. In this work, this coupling relationship was numerically investigated with complete consideration of different cases of heating, and in the view of energy transport and conversion. By comparing with the no-gravity case (NGC), the results indicate that buoyancy has a significant effect on the bottom-heated case (BHC) and side-heated case (SHC), but has little influence on the top-heated case (THC) owing to the different magnitudes of secondary flow. The heat transfer of the BHC and SHC was significantly enhanced by the secondary flow, but their energy conversion was simultaneously impaired. The conversion of the BHC and SHC was approximately half that of the THC and NGC. For all cases, by analyzing the energy transport ways, the cross section can be classified into three regions in the heating direction. Laminar conduction dominates in region I, but gradually fails in region II, where its role is replaced by other energy transport ways. In region III, convection dominates the energy transport for BHC and SHC, whereas turbulence dominates for THC and NGC.

Key words: Heat transfer, Computational fluid dynamics (CFD), Buoyancy, Hydrocarbons

摘要： Although buoyancy and cracking reactions are strongly coupled in the active cooling process, most of the previous studies consider only one of these factors, and their coupling relationship has not been considerably examined. In this work, this coupling relationship was numerically investigated with complete consideration of different cases of heating, and in the view of energy transport and conversion. By comparing with the no-gravity case (NGC), the results indicate that buoyancy has a significant effect on the bottom-heated case (BHC) and side-heated case (SHC), but has little influence on the top-heated case (THC) owing to the different magnitudes of secondary flow. The heat transfer of the BHC and SHC was significantly enhanced by the secondary flow, but their energy conversion was simultaneously impaired. The conversion of the BHC and SHC was approximately half that of the THC and NGC. For all cases, by analyzing the energy transport ways, the cross section can be classified into three regions in the heating direction. Laminar conduction dominates in region I, but gradually fails in region II, where its role is replaced by other energy transport ways. In region III, convection dominates the energy transport for BHC and SHC, whereas turbulence dominates for THC and NGC.

关键词: Heat transfer, Computational fluid dynamics (CFD), Buoyancy, Hydrocarbons

Chengang Yang, Huaizhi Han, Quan Zhu, Xiangyuan Li. Cracking and buoyancy effect on hydrocarbon endothermic and heat transfer characteristics in rectangular mini-channel[J]. Chinese Journal of Chemical Engineering, 2023, 56(4): 242-254.

References

[1] E. Paquette, Cooled CMC Structures for Scramjet Engine Flowpath Components, In: 13th International Space Planes and Hypersonics Systems and Technologies Conference, Capua, Italy (2005).
[2] T.A. Jackson, D.R. Eklund, A.J. Fink, High speed propulsion: Performance advantage of advanced materials, J. Mater. Sci. 39 (19) (2004) 5905–5913.
[3] O.A. Powell, J.T. Edwards, R.B. Norris, K.E. Numbers, J.A. Pearce, Development of hydrocarbon-fueled scramjet engines: The hypersonic technology (HyTech) program, J. Propuls. Power 17 (6) (2001) 1170–1176.
[4] S.L. Zhang, X. Li, J.Y. Zuo, J. Qin, K.L. Cheng, Y. Feng, W. Bao, Research progress on active thermal protection for hypersonic vehicles, Prog. Aerosp. Sci. 119 (2020) 100646.
[5] A. Chen, L. Dang, Characterization of supercritical JP-7's heat transfer and coking properties, In: 40th AIAA Aerospace Sciences Meeting & Exhibit, Reno, NV. Reston (2002).
[6] C. Liang, Y. Wang, S.C. Jiang, Q.Y. Zhang, X.Y. Li, The comprehensive study on hydrocarbon fuel pyrolysis and heat transfer characteristics, Appl. Therm. Eng. 117 (2017) 652–658.
[7] P.X. Jiang, J.J. Yan, S. Yan, Z.L. Lu, Y.H. Zhu, Thermal cracking and heat transfer of hydrocarbon fuels at supercritical pressures in vertical tubes, Heat Transf. Eng. 40 (5–6) (2019) 437–449.
[8] C.G. Yang, Z.J. Quan, Y. Chen, Q. Zhu, J.L. Wang, X.Y. Li, A comprehensive investigation of the pyrolysis effect on heat transfer characteristics for n-decane in the horizon mini-channel, Energy Fuels 34 (1) (2020) 199–210.
[9] Z.J. Jia, H.Y. Huang, W.X. Zhou, F. Qi, M.R. Zeng, Experimental and modeling investigation of n-decane pyrolysis at supercritical pressures, Energy Fuels 28 (9) (2014) 6019–6028.
[10] T.A. Ward, J.S. Ervin, R.C. Striebich, S. Zabarnick, Simulations of flowing mildly-cracked normal alkanes incorporating proportional product distributions, J. Propuls. Power 20 (3) (2004) 394–402.
[11] T.A. Ward, J.S. Ervin, S. Zabarnick, L. Shafer, Pressure effects on flowing mildly-cracked n-decane, J. Propuls. Power 21 (2) (2005) 344–355.
[12] J. Qin, S.L. Zhang, W. Bao, W.X. Zhou, D.R. Yu, Thermal management method of fuel in advanced aeroengines, Energy 49 (2013) 459–468.
[13] Y.H. Zhu, B. Liu, P.X. Jiang, Experimental and numerical investigations on n-decane thermal cracking at supercritical pressures in a vertical tube, Energy Fuels 28 (1) (2014) 466–474.
[14] H. Zhou, X.K. Gao, P.H. Liu, Q. Zhu, J.L. Wang, X.Y. Li, Energy absorption and reaction mechanism for thermal pyrolysis of n-decane under supercritical pressure, Appl. Therm. Eng. 112 (2017) 403–412.
[15] P.H. Liu, T.H. Zhang, L.X. Zhou, Z.C. Chen, Q. Zhu, J.L. Wang, X.Y. Li, Experimental and numerical analysis on flow characteristics and pyrolysis mechanism of hydrocarbon fuel with a novel online hybrid method, Energy Convers. Manag. 198 (2019) 111817.
[16] R.P. Jiang, G.Z. Liu, X.W. Zhang, Thermal cracking of hydrocarbon aviation fuels in regenerative cooling microchannels, Energy Fuels 27 (5) (2013) 2563–2577.
[17] Y. Wang, Y. Zhao, C. Liang, Y. Chen, Q.Y. Zhang, X.Y. Li, Molecular-level modeling investigation of n-decane pyrolysis at high temperature, J. Anal. Appl. Pyrolysis 128 (2017) 412–422.
[18] Z.Z. Li, H.Y. Wang, K. Jing, L.M. Wang, Y. Li, X.W. Zhang, G.Z. Liu, Kinetics and modeling of supercritical pyrolysis of endothermic hydrocarbon fuels in regenerative cooling channels, Chem. Eng. Sci. 207 (2019) 202–214.
[19] W.L. Yu, W.X. Zhou, L. Long, Z.J. Jia, Y.T. He, Effects of different simulation models on pyrolysis performance predictions for regenerative cooling applications, J. Anal. Appl. Pyrolysis 156 (2021) 105136.
[20] W. Bao, S.L. Zhang, J. Qin, W.X. Zhou, K.L. Xie, Numerical analysis of flowing cracked hydrocarbon fuel inside cooling channels in view of thermal management, Energy 67 (2014) 149–161.
[21] K.K. Xu, H. Meng, Modeling and simulation of supercritical-pressure turbulent heat transfer of aviation kerosene with detailed pyrolytic chemical reactions, Energy Fuels 29 (7) (2015) 4137–4149.
[22] Y. Feng, S.L. Zhang, J. Cao, J. Qin, Y. Cao, H.Y. Huang, Coupling relationship analysis between flow and pyrolysis reaction of endothermic hydrocarbon fuel in view of characteristic time correlation in mini-channel, Appl. Therm. Eng. 102 (2016) 661–671.
[23] Y. Feng, Y.G. Jiang, X. Li, S.L. Zhang, J. Qin, Y. Cao, H.Y. Huang, Numerical study on the influences of heat and mass transfers on the pyrolysis of hydrocarbon fuel in mini-channel, Appl. Therm. Eng. 119 (2017) 650–658.
[24] Z.Z. Li, Y. Li, X.W. Zhang, G.Z. Liu, Coupling of pyrolysis and heat transfer of supercritical hydrocarbon fuel in rectangular minichannels, Chem. Eng. Sci. 247 (2022) 116924.
[25] G.Z. Zhao, W.Y. Song, R.L. Zhang, Effect of pressure on thermal cracking of China RP-3 aviation kerosene under supercritical conditions, Int. J. Heat Mass Transf. 84 (2015) 625–632.
[26] X. Li, S.L. Zhang, M. Ye, J. Qin, W. Bao, N.G. Cui, X.Y. Liu, C.Y. Zhou, Effect of enhanced heat transfer structures on the chemical recuperation process of advanced aero-engine, Energy 211 (2020) 118580.
[27] Y. Feng, Y. Cao, S.Y. Liu, J. Qin, A.A. Hemeda, Y.B. Ma, The influence of coking on heat transfer in turbulent reacting flow of supercritical hydrocarbon fuels, Int. J. Heat Mass Transf. 144 (2019) 118623.
[28] Y. Chen, Z.L. Lei, T.H. Zhang, Q. Zhu, Z.W. Bao, Q.Y. Zhang, X.Y. Li, Flow distribution of hydrocarbon fuel in parallel minichannels heat exchanger, AIChE J. 64 (7) (2018) 2781–2791.
[29] Y. Chen, B. Liu, Z.L. Lei, Q.Y. Zhang, Q. Zhu, Z.W. Bao, X.Y. Li, A control method for flow distribution in fuel-cooled plate based on choked flow effect, Appl. Therm. Eng. 142 (2018) 127–137.
[30] J.Q. Zhu, K.H. Tao, Z. Tao, L. Qiu, Heat transfer degradation of buoyancy involved convective RP-3 hydrocarbon fuel in vertical tubes with various diameters under supercritical pressure, Appl. Therm. Eng. 163 (2019) 114392.
[31] X. Sun, H. Meng, Large eddy simulations and analyses of hydrocarbon fuel heat transfer in vertical upward flows at supercritical pressures, Int. J. Heat Mass Transf. 170 (2021) 120988.
[32] X. Sun, H. Meng, Y. Zheng, Asymmetric heating and buoyancy effects on heat transfer of hydrocarbon fuel in a horizontal square channel at supercritical pressures, Aerosp. Sci. Technol. 93 (2019) 105358.
[33] F. Sun, Y. Li, B. Sunden, G.N. Xie, The transport and thermodynamic characteristics of thermally oscillating phenomena in a buoyancy-driven supercritical fuel flow, Int. J. Therm. Sci. 159 (2021) 106550.
[34] K.K. Xu, X. Sun, H. Meng, Conjugate heat transfer, endothermic fuel pyrolysis and surface coking of aviation kerosene in ribbed tube at supercritical pressure, Int. J. Therm. Sci. 132 (2018) 209–218.
[35] K.K. Xu, B. Ruan, H. Meng, Validation and analyses of RANS CFD models for turbulent heat transfer of hydrocarbon fuels at supercritical pressures, Int. J. Therm. Sci. 124 (2018) 212–226.
[36] F.R. Menter, Two-equation eddy-viscosity turbulence models for engineering applications, AIAA J. 32 (8) (1994) 1598–1605.
[37] D.Y. Peng, D.B. Robinson, A new two-constant equation of state, Ind. Eng. Chem. Fund. 15 (1) (1976) 59–64.
[38] T.H. Chung, M. Ajlan, L.L. Lee, K.E. Starling, Generalized multiparameter correlation for nonpolar and polar fluid transport properties, Ind. Eng. Chem. Res. 27 (4) (1988) 671–679.
[39] E.N. Fuller, K. Ensley, J.C. Giddings, Diffusion of halogenated hydrocarbons in helium. The effect of structure on collision cross sections, J. Phys. Chem. 73 (11) (1969) 3679–3685.
[40] S. Takahashi, Preparation of a generalized chart for the diffusion coefficients of gases at high pressures, J. Chem. Eng. Japan 7 (6) (1975) 417–420.
[41] T.R. Marrero, E.A. Mason, Gaseous diffusion coefficients, J. Phys. Chem. Ref. Data 1 (1) (1972) 3–118.
[42] B. Zappoli, D. Beysens, Y. Garrabos, Heat Transfers and Related Effects in Supercritical Fluids, Springer, Dordrecht, 2015.
[43] G. Jaeger, The Ehrenfest classification of phase transitions: Introduction and evolution, Arch. Hist. Exact Sci. 53 (1) (1998) 51–81.
[44] T.L. Bergman, A.S. Lavine, F.P. Incropera, D.P. Dewitt, Fundamentals of Heat and Mass Transfer, John Wiley & Sons, New York, 2018.
[45] Y.Q. Chen, Y. Li, B. Sunden, G.N. Xie, The abnormal heat transfer behavior of supercritical n-decane flowing in a horizontal tube under regenerative cooling for scramjet engines, Appl. Therm. Eng. 167 (2020) 114637.
[46] J.D. Jackson, Fluid flow and convective heat transfer to fluids at supercritical pressure, Nucl. Eng. Des. 264 (2013) 24–40.
[47] Y.L. Cui, New analytical method for single-phase convective heat transfer and unified mechanism analyses on buoyancy-induced supercritical convective heat transfer deterioration, Int. J. Heat Mass Transf. 146 (2020) 118871.